• 한국정밀공학회지
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• 제20권3호
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• pp.172-177
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• 2003

This paper investigates the effect of reinforced plate on the deflection of the rectangular plate, when the rectangular plate is reinforced with rectangular rigid body at the centroid of the plate. For two boundary conditions such as simple supported and clamped boundary This study derives deflection formula of reinforced plates with three kinds of the aspect ratio of a rectangular plate with respect to the elastic modulus ratio and the length ratio of rigid body using the least square method. The results are as follows: 1. As the elastic modulus ratio r$_{e}$$\geq$ 1000, the maximum deflection with respect to the length ratio r$_{1}$ converges into constant value. 2. Deflection formula with respect to the length ratio r$_{1}$ is derived as the third order polynomial.l.

• Journal of Biosystems Engineering
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• 제18권3호
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• pp.262-269
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• 1993

Stress relaxation behaviors of the cucumber under bending moment were tested with UTM at three levels of loading rate and initial deflection ratio. Sample cucumber was selected from three cultivars of cucumber, Cheongjangmadi, Baekdadagi, and Gyeousalicheongjang, because these cultivars are the most popular grown cultivars in Korea. When the bending moment was applied to the cucumber sample, the effective span between simple supports was held a constant value of 116mm with consideration of the selected sample length. The objectives of this study were to develop the rheological models such as linear and nonlinear models of the stress relaxation for the cucumber samples, and to investigate the effects of loading rate and initial deflection ratio on the stress relaxation behavior of the cucumber. The results of this study may be summarized as follows : 1. Stress relaxation behavior of the cucumber could be well described by the generalized Maxwell model for each level of deflection ratio. But the stress relaxation behavior of the sample was found to be initial deflection ratio and time dependent, and it was represented the nonlinear viscoelastic model as a function of initial deflection ratio and time. 2. Stress relaxation behavior of the cucumber samples was very highly affected by the loading rate and the initial deflection ratio. The more loading rate and initial deflection ratio resulted in the more initial bending stress and after stress relaxation progressed more rapidly. 3. At the same test conditions, it was found that the stress relaxation rate of Cheongjangmadi was faster than that of other cultivars.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제28권1호
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• pp.71-89
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• 2021

We define the constant ratio curves in the isotropic plane and investigate their deflection properties.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.97-103
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• 2002

Vibration isolation technology using an air spring and laminated rubber bearing is widely used because it has excellent vibration isolation characteristics. In the part of that, we usually make use of the self-damped air suing. It is occupied two chambers, restrictor, diaphragm and load plate. Two chambers contain compressed air and the volume of chambers and the area of load plate give a definition of stiffness and load. The restrictor and the volume ratio of two chambers give a definition of damping ratio. The conventional model of restrictor is made of one orifice and it causes turbulent flow in the orifice at the region of large deflection. The stillness of air suing is larger and the damping is lower in the region of large deflection. In the multi-orifice case, the stiffness is similar to air spring with one orifice but damping ratio is larger than conventional air spring. And damping ratio is smaller than conventional air suing in small deflection region. Deflection is small in the region of high frequency so small damping is better than large damping. As a result, we can reduce the storage stiffness of air suing in the wide region of deflection and increase the damping ratio in the region of large deflection. After this, we will try to and the relation of Reynolds Number and Flow Resistance then we are going to make another restrictor for air spring to improve damping ratio and stiffness.

• 복합신소재구조학회 논문집
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• 제4권2호
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• pp.31-38
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• 2013

As the Sewer Pipe is transformed by the expansion of life cycle as a result of the technology development, flexible pipe is developed by the transformed environmental conditions. To change pipe design, three phases(compaction ration - inner deflection ratio - ring stiffness) should be considered in design conditions. The input data of pipe design were provided by compaction-inner deflection ratio-ring stiffness. M oreover, The guidelines of sewerage pipes should be considered by flexible pipes design criteria.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.869-872
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• 2002

This paper deals with the effect of reinforced plate on the deflection of the rectangular plate, when the rectangular plate is reinforced with rectangular rigid body at the centroid of the plate. For Two boundary conditions such as simple supported and clamped boundary, this study derives deflection formula of reinforced plates with respect to the stiffness ratio and the length ratio of rigid body using the least square method. The results are as follows: 1. As $r_e$ $\geq$ 1000, the maximum deflection with respect to $r_e$ converges into constant value. 2. Deflection formula with respect to $r_e$ is derived as the fifth order polynomial.

• 대한토목학회논문집
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• 제31권1A호
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• pp.35-41
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• 2011

콘크리트구조설계기준에서는 일반적으로 처짐을 제어하기 위해 직접처짐제어법과 간접처짐제어법을 제시하고 있다. 이 때 처짐/깊이-비는 허용 처짐량을 초과하지 않도록 제한된다는 점에서 간접처짐제어법이 더 효과적이다. 실제 처짐량은 많은 요소에 의해 영향을 받기 때문에 실제 처짐량을 정확하게 산정하는 것은 어렵다. 이 연구에서는 철근콘크리트 부재의 사용한 계상태에서 처짐량을 직접 계산함으로써 한계 지간/깊이-비를 산정하였다. 이 때 처짐은 재료 모델로부터 산정된 휨곡률을 통해 산정하였다. 해석의 주요 변수는 인장증강효과 모델, 콘크리트 강도, 단면 크기 및 압축 철근의 유무이다. 해석 결과 2차식 형태의 인장증강효과 모델을 사용함으로써 해석의 일관성을 도모할 수 있는 것으로 나타났다. 또한 한계 지간/깊이-비는 단면 크기와 관계없이 재료 강도와 인장 및 압축 철근비에 따라 변화하는 것으로 나타났다.

• Structural Engineering and Mechanics
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• 제91권4호
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• pp.335-347
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• 2024

This paper presents the behavior of geopolymer concrete beams reinforced with glass fiber reinforced polymer (GFRP) bars. In the study, ordinary Portland cement concrete and geopolymer concrete beams having GFRP bars were prepared and tested under four-point loading. The load-deflection diagrams and load capacities of the tested beams were obtained. It was observed that the tested beams exhibited good ductility and significant deflection capacity. The results showed that increasing the tension GFRP reinforcement ratio caused enhancement in the strength capacity of geopolymer concrete beams. In addition, the tested beams were analyzed to obtain the load capacity and the load-deflection responses. The theoretical load-deflection curves and load bearing capacities have been predicted well with the test results. Parametric study has been performed to determine the influences of concrete strength, shear span to depth ratio (a/d) and reinforcement ratio on the behavior of geopolymer concrete beams longitudinally reinforced with GFRP bars. It was concluded that increasing concrete strength led to an increase in load capacity. Besides, the ultimate load increased as the reinforcement ratio increased. On the other hand, increasing a/d ratio reduced the ultimate load value of GFRP reinforced geopolymer concrete beams.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.37-40
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• 2006

In this paper, long term deflection of RC beam with variable substitution ratio of recycled aggregate is investigated. 6 RC beam specimens are designed using concrete made of coarse aggregate of 25mm size, mix strength of 21MPa, slump of 12cm and air content of $5.0{\pm}1.5%$. A few concrete blocks are made and used for long term loading. The loading and deflection instrumentation are conducted following the process codified in ACI 318-05 code. Test result shows that the deflection of specimens depends on the compressive strength of concrete. And it is concluded that the deflection of RC beam can be predicted like normal beam using ACI formula if certain level of compressive strength is acquired even recycled aggregate is used in making the beam.

• Structural Engineering and Mechanics
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• 제19권4호
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• pp.401-411
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• 2005

The influence of cracks on the elastic deflection and ultimate bearing capacity of eccentric thin-walled columns with both ends pinned was studied in this paper. First, a method was developed and applied to determine the elastic deflection of the eccentric thin-walled columns containing some model-I cracks. A trigonometric series solution of the elastic deflection equation was obtained by the Rayleigh-Ritz energy method. Compared with the solution presented in Okamura (1981), this solution meets the needs of compatibility of deformation and is useful for thin-walled columns. Second, a two-criteria approach to determine the stability factor ${\varphi}$ has been suggested and its analytical formula has been derived. Finally, as an example, box columns with a center through-wall crack were analyzed and calculated. The effects of cracks on both the maximum deflection and the stability coefficient ${\varphi}$ for various crack lengths or eccentricities were illustrated and discussed. The analytical and numerical results of tests on the columns show that the deflection increment caused by the cracks increases with increased crack length or eccentricity, and the critical transition crack length from yielding failure to fracture failure ${\xi}_c$ is found to decrease with an increase of the slenderness ratio or eccentricity.